Sterile liquid entraining system

ABSTRACT

A sterile liquid entraining system includes a vapor generator and a liquid container. Initially, the container is sterilized and is filled with a sterile liquid. Then, the vapor generator is connected to the container and the sterile liquid is fed from the liquid container into the vapor generator. As the liquid flows from the container into the vapor generator, the container is filled with a sterile gas, preferably by directing the gas through a microorganism impervious filter. Because the sterile liquid in the container is replaced with a sterile gas, the sterility of the interior of the container is maintained throughout the operation of the vapor generator.

United States Paten n91 Deaton [451 May 7,1974

[75] Inventor:

[73] Assignee: Deaton Medical Company, Burns Flat, Okla.

22 Filed: Sept. 5, 1972 21 Appl. No.: 286,085

Related US. Application Data [63] Continuation of Ser. No. 57,028, June 24, 1970,

[56] References Cited UNITED STATES PATENTS 3,010,910 11/1961 Gauchard 128/194 X 3,075,523 l/l963 Eichelman 128/194 X 5/1923 Blackwood 128/186 9/1970 Grosholz 128/188 3,593,710 7/1971 Eichelman 128/188 Primary Examiner-Richard A. Gaudet Assistant Examiner--G. F. Dunne Attorney, Agent, or Firm-Richards, Harris & Medlock [57] 1 ABSTRACT V A sterile liquid entraining system includes a vapor generator and a liquid container. Initially, the container is sterilized and is filled with a sterile liquid. Then, the vapor generator. is connected to the container and the sterile liquid is fed from the liquid container into the vapor generator. As the liquid flows from the container intothe vapor generator, the container is filled with a sterile gas, preferably by directing the gas through a microorganism impervious filter. Because the sterile liquid in the container is replaced with a sterile gas, the sterility of the interior of the container is maintained throughout the operation of MTENTEDMAY 7 I974 SHEET 2 [1F 3 PATENIEDMAY 11574 v 3.809.080

I SHEEIBUFB FIG. 4 al '1 STERILE LIQUID ENTRAINING SYSTEM RELATED APPLICATIONS This application is a continuation of application Ser. No. 57,028, filed June 24, 1970 now abandoned.

BACKGROUND or THE INVENTION In the practice of the healing arts, a wide variety of ailments are treated by means of inhalation therapy, that is by administering various gases, including oxygen, oxygen enriched air, etc., to patients through to employ liquid entraining systems in conjunction with inhalation therapy systems.

At the present time two types of liquid entraining systems are in use. These include humidifiers, which traditionally generate a vapor comprising the gaseous state of a liquid, and nebulizers, which generate a vapor comprising very small liquid droplets. In the operation of both humidifiers and nebulizers, a liquid from a reservoir is transformed into a vapor, and the vapor is entrained in a medicinal gas as the gas is administered.

f Thereservoirs that are employed in conjunction with presently available liquid entraining systems comprise refillable glass jars. Liquid entraining system reservoirs of this type are unsatisfactory for a number of reasons. For example, hospital personnel often forget to sterilize the jars between uses. Even ifa jar is sterilized, there is no guarantee that the liquid that is used to fill the jars is sterile. And, at the present time, the liquid that is withdrawn from ,a liquid entraining system reservoir is replaced with unfiltered room air. Microorganisms carried into a reservoir with the air can contaminate the interior of the reservoir,'even though the interior was initially sterile.

Regardless of the manner in which microorganisms are introduced into a liquid entraining system reservoir, there is ample time for the microorganisms to multiply I within the reservoir. This is because modern liquid entraining systems are capable-of operating for as long as 8 hours before it is necessary to refill the reservoir. During the latter stages of the operation of sucha liquid entraining system, microorganisms that have multiplied within the reservoir are carried out of the reservoir with the liquid, and are entrained in a medicinal gas along with the vaporthat is generated from the liquid.

As is fully documented in the paper entitled Colonization of Infants Exposed to Bacterially Contaminated 'Mists wirtten by Hugh L. Moffett and David Allan and published in the American Journal of Diseases of Children, Volume 114, July 1967 pages 21-25, the introduction of microorganisms into medicinal gases is a dangerous practice. Thus, a need exists for a liquid entraining system in which the interior of the reservoir is maintained sterile throughout the use of the system. The present invention fulfills this need, in that it comprises a liquid entraining system in which the reservoir is sterilized and filled with a sterile liquid prior to use, and in which contact between the liquid and unfiltered air is prevented during use.

SUMMARY OF THE INVENTION In accordance with the preferred embodiment of the invention, a sterile liquid entraining system includes a vapor generator, a container for supplying liquid to the vapor generator and structure for filling the container with a sterile gas as liquid is withdrawn therefrom. Preferably, the latter structure includes a filter that removes microorganisms from the gas as the gas is fed into the container. In this way, the contamination of the liquid in the container is prevented, in that the sterility of the interior of the container is maintained throughout the operation of the vapor generator.

DESCRIPTION OF THE DRAWINGS A more complete understanding of the invention may be had by referring to the following Detailed Description when taken in conjunction with the drawings, wherein:

FIG. 1 is a sectional view of a liquid container;

FIG. 2 is a sectional view of a nebulizer;

FIG. 3 is an illustration of a first embodiment of the invention in which the nebulizer shown in FIG. 2 is used in conjunction with the liquid container shown in FIG. I; v t

FIG. 4 is a sectional view showing a modified version of the nebulizer shown in FIG. 2;

FIG. 5 is a sectional view showing another modified version of the nebulizer shown in FIG. 2, and

. FIG. 6 is an illustrationof a second embodiment of the invention; w

DETAILED DESCRIPTION Referring now to the drawings, a sterile liquid entraining system employing the. present invention is shown. Referring particularly to FIG. 1, there is shown va liquid container 10 useful in the practice of the invention. The liquid container 10 includes abottle 12 which turing techniques, and comprises an open top 14, a

threaded neck 16 and two pairs of bail receiving buttons 18.

The liquid container 10 further includes a support bail 20 that is mounted in selected pairs of the bail receiving buttons 18 to suport the bottle 12. A sopper assembly 22 is mounted over the opentop 14 of the bottle l2 and comprises a cap 24, a water outlet port 26, and an air inlet port 28. The cap 24 is formed from a flexible, sterilizable, microorganism impervious substance, such as rubber, polyethylene, etc. The ports 26 and 28 comprise tubes mounted in the cap 24.

In the use of the liquid container 10, the bottle 12 and the stopper assembly '22 are initially sterilized. Then the bottle 12 is filled with a medically sterile liquid 32. The liquid 32 may comprise water or any other liquid and may include dissolved medicaments, if desired.

When the bottle 12 is full, the stopper assembly 22 is positioned over the open top 14 of the bottle. Then, 7

3 the practice of the invention. The nebulizer 40 includes a housing 42 which defines a nebulizing chamber 44. The housing 42 has a plurality of ports formed in it, including a liquid inlet port 46, a dry gas inlet port 48, a vapor outlet port 50 and a gas outlet port 52.

The gas inlet port 48 has a valve 54 mounted in it which mey be opened to facilitate the use of the nebulizer 40 in a mainstream application, or closed to facilitate the use of a nebulizer in a side stream application. The liquid inlet port 46 comprises an elongate tube having an outside diameter substantially equal to the inside diemater of the port 26 of the liquid container 10, and having a length substantially equal to the height of the container 10. The gas outlet port 52 comprises a tube having an outside diameter substantially equal to the inside diameter of the port 28 of the container 10, and having a microorganism impervious filter 56 mounted in it. The filter 56 may comprise any of the commercially available microorganism impervious, combination liquid and gas filters, such as the various filters manufactured 'by The Millipore Corporation under the trademarks MF-MILLIPORE, DURA- LON, SOLVINERT, CELOTATE, MITEX, POLYVIC, MICROWEB, and AQUAPEL.

The operating portions of the nebulizer 40 comprise a pressurized gas inlet tube 58, a liquid delivery tube 60, and a target 62. The liquid delivery tube 60receives liquid through the liquid inlet port 46, and directs the liquid to a liquid delivery orifice 64. The gas inlet tube 60 directs a high velocity jet of oxygen, air or the like across the orifice 64, whereupon liquid is drawn out of the orifice and liquid droplets are entrained in the gas jet.

The target 62 is supported in the housing 42 of the nebulizer 40 by a pin and hole connection 66. When the target 62 is removed, the gas jet flowing from the tube 60 and the liquid droplets entrained therein are directed out of the nebulizer 40 through the vapor outlet port 50. When the target 62 is positioned in the manner shown in FIG. 2, the droplets entrained in the jet are directed into engagement with the target 62. They engagement of the droplets with the target 62 breaks the droplets into very small droplets having diameters ranging up to about microns. The small droplets are then directed out of the nebulizer 40 through the vapor outlet port 50. At the same time, a portion of the liquid comprising the droplets that engage the target 62 flows down the target 62 into the bottom of the nebulizing chamber 44. A more complete description of the operation of nebulizers of the type shown in FIG. 2 is contained in US. Pat. No. 3,172,406.

The use of the nebulizer 40 in conjunction with the liquid container l0is illustrated in FIG. 3. Initially, the cover 36 and the tear away stoppers 34 are removed from the liquid container 10. As the stoppers 34 are removed, air rushing into the bottle 12 generates the hissin'g sound, which is indicative of the sterility of the contents of the container 10. Then, the exteriors of the ports 46 and 52 of the nebulizer 40 are sterilized, and the nebulizer 40 is coupled to the container by inserting the liquid inlet and the gas outlet ports 46 and 52 of the nebulizer 40 through the ports 26 and 28 of the container 10, respectively. The ports 26, 28, 46 and 52 are so constructed that the interior of the bottle 12 is sealed when the nebulizer 40 is mounted on the liquid container 10.

After the nebulizer 40 and the liquid container 10 are interconnected, the-pressurized gas inlet tube 58 of the nebulizer 40 is connected to a source of pressurized gas, and the vapor outlet port 50 is coupled to a patient through suitable hoses, tents, etc. If the nebulizer 40 is to be used in a main stream application, a source of dry gas is connected to the dry gas inlet port 48, or the port 48 is opened to the atmosphere, as desired. Then, the nebulizer 40 is operated either with or without the target 62 in place to direct a vapor to the patient through the vapor outlet port 50.

During the useof the nebulizer 40, the medically sterile liquid 32 is supplied to the nebulizer 40 from the liquid container 10. As the liquid is withdrawn from the bottle 12, an equal volume of gas flows into the bottle through the gas outlet port 52. Because of the filter 56 in the port 52, any microorganisms in the gas flowing through the port 52 are removed from the gas before the'gas enters the bottle 12. Thus, the filter 56 eliminates any possibility of contamination of the'interior of the bottle 12'due to microorganisms in the gas entering the bottle 12.

When the nebulizer 40 is operated with the target 62 in place, liquid continuously flows down the target 62 into the lower portion of the nebulizing chamber 44.

This liquid collects in the nebulizing chamber 44 until it reaches a depth equal to the height of the gas outlet port 52. Then, the liquid is returned to the bottle 12 through the gas outlet port 52. Again, the filter 56 removes all microorganisms from the liquid entering the bottle 12, so that any danger of contaminating the contents of the bottle 12 is eliminated. I

Referring now to FIG. 4, a nebulizer 40' comprising a modified version of the nebulizer shown in FIG. 2 is illustrated. The nebulizer 40 is identical to the nebulizer 40 except that it includes a needle valve 68 mounted in the gas outlet tube 52. In the use of the nebulizer 40', the valve 68 is operated to control the rate of flow of gas into the bottle 12. This in turn controls the rate of flow of the liquid 32 out of the bottle.

The nebulizer 40 also differs from the nebulizer 40 in that it includes a liquid outlet port 70, which may comprise a hole in the housing 42, or a check valve, as desired. In the use of the nebulizer 40, liquid accumulating in the bottom of the nebulizing chamber 44' is not returned to the bottle 12 through the filter 56'.

Rather, the liquid is drained from the housing 42 through the liquid outlet port 70. Thus, the filter 56' may comprise a microorganism impervious filter suitable for use with gases only.

A nebulizer 40" comprising another modified version of the nebulizer 40 is shown in FIG. 5. The nebu- When the nebulizer 40" is employed in conjunction with the liquid supply container 10 shown in FIG. 1, the regulator 74 is adjusted to provide an outlet pressure slightly above atmospheric pressure. Then, the needle valve is regulated to control the rate of flow of liquid from the bottle 12 to the nebulizing chamber 14". The interior of the bottle 12 of the liquid container is thus maintained at a pressure slightly above atmospheric pressure which prevents microorganisms from entering the interior of the container 12 through any portion of the stopper assembly 22. Since the air entering the container 10 through the port 72 passes through the filter 76, any possibility of contaminating the inter ior of the bottle 12 is eliminated.

Referring now to FIG. 6, a second embodiment of the present invention is shown. In accordance with the second embodiment, a collapsible liquid container 100 is formed from sterilizable, microorganism impervious substance, for example, a poly-l-olefin, such as polyethylene, polypropylene, etc., a polyamid, such a ny .lon, etc. The collapsible liquid container 100 is preferably formed from flexible sheets which are joined into a flexible bag by conventional bonding techniques, such as heat sealing. The collapsible liquid container 100 includes a main portion 102 having a support bale 104 secured to its upper end having a nebulizer receiving port 106 secured to its lower end. The port 106 preferably comprises an inwardly tapered, normally sealed tube that is mounted between the sheets comprising the collapsible liquid container 100.

In the use of the collapsible liquid container 100, the interior of the main portion 102 is initially sterilized. A medically sterile liquid 108 is then fed into the interior of the container 100. The sterile liquid 108 may comprise water or any other liquid, and may include dissolved medicaments, as desired. After a predetermined amountof liquid 108 has been fed into the main portion 102 of the container 100, the container 100 is sealed, so that the liquid 108 remains sterile throughout the transportation and/or storage of the container 100.

A nebulizer 110 suitable for use in conjunction with the liquid container 100 is also illustrated in FIG. 6. The nebulizer 110 includes a housing 112 which defines a nebulizing chamber 114. The housing 112 has a pluralityof ports formed in it, including a combined liquid inlet, gas outlet port 116, a dry gas inlet port 118 and a vaporoutpet port 120. The dry gas inlet 118 has a valve 122 mounted in it which may be opened to facilitate. the use of the nebulizer 1 10 in a mainstream application, or closed to facilitate the use of the nebulizer 110 in a side stream application.

The combined liquid inlet, gas outlet port 116 includes a liquid inlet tube 124 and a somewhat shorter gas outlet tube 126 having a microorganism impervious filter 128 mounted in it. The upper portion of the port 116 is circular in shape and has an outside diameter substantially equal to the average inside diameter of the port 106 of the collapsible liquid container 100. The upper end of the port 116 is provided with retaining barbs 130 which cooperate with the port 106 to secure the nebulizer 110 to the collapsible liquid container 100 in the manner shown in FIG. 6.

The operating portions of the nebulizer 100 comprise a pressurized gas inlet tube 132, a liquid delivery tube 134, and a target 136. The liquid delivery tube 134 receives liquid from the bottom of the nebulizing chamber 114 thorugh an aperture 138, and directs the liquid to a chamber liquid delivery orifice 140. The gas inlet tube 132 directs a high velocity jet of oxygen, air, or the like across the orifice 140, whereupon liquid is drawn 6 out of the liquid delivery tube 134 and liquid droplets are entrained in the gas jet.

The target 136 is supported in the housing 112 of the nebulizer 110 by a pin and hole connection 142. When the target 136 is removed, the gas jet flowing from the tube 132 and the liquid droplets entrained therein are directed of the nebulizer 110 through the vapor outlet port 120. When the target 136 is positioned in the manner shown in FIG. 6, the droplets are entrained in the gas jet are directed into engagement with the target 136. This action breaks the droplets into very small droplets having diameters ranging up to about 5 microns. The gas jet and the small diameter droplets entrained therein are then directed out of the nebulizer 110' through the vapor outlet port 120. At the same time, a portion of the liquid comprising the droplets that engage the target 136 flowsdown the target 136 into the bottom of the nebulizing chamber 114.

In the practice of the second embodiment of the invention, the combined liquid inlet, gas outlet port 116 of the nebulizer 110 is inserted into the port 106 of the collapsible liquid container 100. Then, the pressurized gas inlet tube 132 is' connected to a source of pressurized gas, and the vapor outlet port 120 is coupled to a patient through suitable hoses, tents, etc. If the nebulizer 110 is to be used in a main stream application, a source of dry gas is connected to the dry gas inlet port 118, or the port 118 is opened to the atmosphere, as required. Then, the nebulizer 110 is operated either with or without the target 136 in place to direct a vapor to the patient through the vapor outlet port 120.

During the use of the nebulizer 110, liquid is directed into the bottom of the nebulizing chamber 114 through the liquid supply tube 114. As liquid is withdrawn from the collapsible liquid container 100, an equal volume of gas flows into the container 100 through the gas inlet tube 126. Any microorganisms that are present in the gas flowing through the tube 136 are removed by the filter 5128. Thus, the interior of the container 100 remains medically sterile throughout the use of the second embodiment of the invention. The tube 126 also regulates the depth of the liquid in the bottom of the nebulizing chamber 114 by preventing gas from flowing into the container 100 after the liquid reaches a predetermined depth.

It will be understood that various modifications of the embodiments shown in the drawings can be employed in the practice of the invention. For example, if a sterile gas is supplied to the regulator 74 of the nebulizer 40" shown in FIG. 5, the filter 76 can be dispensed with.

Also, a nebulizer constructed similarly to the nebulizer 110 shown in FIG. 6 can be employed in conjunction with the liquid container 10 shown in FIG. 1. In the latter case, the liquid container 10 is oriented with the top 14 facing downwardly.

From the foregoing, it will be understood that the present invention comprises a sterile liquid entraining system including a vapor generator, a container for supplying liquid to the vapor generator, and a structure for filling the container with a sterile gas as liquid is withdrawn therefrom. The container fulling structure preferably includes a filter for removing microorganisms from the gas as it flows into the container. By this means, the sterility of the interior of the container is maintained throughout the use of the vapor generator, and the possibility of entraining microorganisms in a medicinal gas along with the vapor produced by the vapor generator is eliminated.

Although specific embodiments of the invention are illustrated in the drawings and described herein, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of rearrangement, modification and substitution of parts and elements without departing from the spirit of the invention.

What is claimed is:

l. A medical nebulizer comprising:

a container for containing a supply of liquid,

a nebulizer housing mounted to said container,

a gas inlet in said nebulizer housing for receiving pressurized gas such that a stream of gas is directed within said housing,

a conduit extending from said container to the region of said gas inlet for supplying liquid to said stream of gas due to venturi action,

a target mounted in said housing and positioned adjacent said gas inlet in the path of said stream of gas and liquid such that vapor is formed,

vapor outlet means in said housing for transmitting vapor to a patient area,

passageway means formed between said housing and said container for gas and excess liquid to flow from said housing to said container, and

filter means in said passageway for filtering microorganisms from the gas and'liquid flowing through said passageway into said container.

2. The nebulizer of claim 1 and further comprising:

means for regulating the rate at which said container is filled with gas and thereby regulating the rate at container. 

1. A medical nebulizer comprising: a container for containing a supply of liquid, a nebulizer housing mounted to said container, a gas inlet in said nebulizer housing for receiving pressurized gas such that a stream of gas is directed within said housing, a conduit extending from said container to the region of said gas inlet for supplying liquid to said stream of gas due to venturi action, a target mounted in said housing and positioned adjacent said gas inlet in the path of said stream of gas and liquid such that vapor is formed, vapor outlet means in said housing for transmitting vapor to a patient area, passageway means formed between said housing and said container for gas and excess liquid to flow from said housing to said container, and filter means in said passageway for filtering microorganisms from the gas and liquid flowing through said passageway into said container.
 2. The nebulizer of claim 1 and further comprising: means for regulating the rate at which said container is filled with gas and thereby regulating the rate at which liquid is supplied through said conduit.
 3. The nebulizer of claim 1 wherein said container and said nebulizer housing are separately constructed and are adapted to be mounted together, said container having flexible walls.
 4. The nebulizer of claim 3 wherein said container includes a top having apertured with removable stoppers positioned therein, whereby upon heating of said container a vacuum is created within said Container and said stoppers maintain said vacuum within said container. 